LaserMax makes one HELL of a product. Always zero'ed, batteries last a hell of a long time, integral power button (xd's have it in a modified takedown lever), and never had ANY mechanical problems with the replacement spring/laser shooting cheapo crap to Federal +P HST's even. 110% sure that every carry gun I ever own will be equipped with one. Also, it's the perfect dry-fire tool because you can two-eye and see if you jerk, or one-eye and ask a friend to watch to see if the laser jerks on the wall. A+
...only thing is it's ass expensive compared to externals, and since the XD already has a pic rail on it, if it's a home defense gun and won't be holstered, there's really no advantage to the integral guide-rod to justify the expensive price.